Seam protecting mechanism for cloth shearing machines



April 5, 1938- I c. H. COOLIDGE 2,112,905

SEAM PROTECTING MECHANISM FOR CLOTH SHEARING MACHINES Filed Nov. 25, 1935 2 Sheets-Sheet 1 Patented Apr. 5, 1938 UNlTED STATES PATENT OFFIQE SEAM PROTECTING MECHANISM FOR CLOTH SHEARING MACHINES Application November 25, 1935, Serial No. 51,460

15 Claims.

This invention relates to machines for shearing cloth as a part of the finishing thereof. In such machines as commonly used, the cloth is drawn between a rapidly rotating shearing cutter or revolver and some kind of a cloth support which is normally maintained in close relationship to said cutter. In order to lead successive pieces of cloth through such a machine, the trailing end of one piece of cloth is usually stitched to the leading end of the next piece of cloth, thus producing a seam which will not pass uninjured through the narrow opening between the revolving cutter and the cloth support.

Various devices have been proposed for temporarily separating the cutter and cloth support, but these devices have usually been found unsatisfactory in certain respects, and the separation of the cutter and cloth support has been commonly performed manually by the machine operator, which necessitates continued attendance and constant watchfulness.

It is the general object of my invention to provide improved seam. protecting mechanism for a cloth shearing machine, by which the revolving cutter and the cloth support may be temporarily and automatically separated under the control of the seam, and by the use of which the period of necessary separation will be made as short as is operatively possible.

A more specific object of my invention is to provide improved means for temporarily and automatically removing a revolving shearing cutter from operative position and for thereafter returning the same to operative position, all without shock or jar and within a minimum length of cloth travel.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of the invention is shown in the drawings, in which Fig. 1 is a side elevation of portions of a cloth shearing machine embodying my improvements;

Fig. 2 is a side elevation of certain additional parts;

Fig. 3 is an end elevation, partly in section, of the seam detecting mechanism, and

Fig. 4 is a diagram of certain electrical circuits.

Referring to Fig. 1, I have shown portions of a cloth shearing machine comprising a fixed frame H] on which are mounted stands I l at each side of the machine. Bearing blocks l2 are sea cured to the stands II by clamping bolts l3 and may be adjusted along inclined guideways by adjusting screws I4.

Arms 15 are pivoted at I6 to the bearing blocks l2 and rotatably support a cutter or revolver l8, preferably provided with a plurality of helical cutting blades 19. The cloth C is drawn through the machine by winding or feed mechanism (not shown) and the path of travel of the cloth is determined by a series of guide-rolls 20, 2|, 22, 23, and 24 and by a fixed cloth support 25 over which the cloth C is drawn at a relatively sharp angle.

The cutter or revolver I8 is mounted adjacent the cloth support 25 and may be adjusted relative thereto by stop screws 21, by which the cutter may be swung toward or away from the cloth support.

In the operation of the machine above described, it is necessary to swing the cutter or revolver I8 away from the fixed cloth support whenever a seam S (Fig. 3) in the cloth C approaches the cloth support.

In order to effect this result manually, the machine is commonly provided with foot levers 30 (Fig. 2) secured to a cross shaft 3| pivotally mounted in the frame 10. The levers 30 are connected by elongated upright links 32 to the upper ends of the arms l5 which rotatably support the cutter 18. By downward pressure on one of the foot levers 30, the cutter may be swung. away from the cloth support 25 and may be maintained in such inoperative position for any desired period.

The parts thus far described are or may be of the usual commercial construction.

For the purpose of automatically moving the cutter l8 away from operative position, I have provided additional power-operated means for actuating the levers 30 and links 32.

For the accomplishment of this purpose, I preferably provide a motor M having a crank arm 40 (Fig. 2) secured to the motor shaft and slotted to adjustably receive a crank-pin 4| which extends freely through an elongated slot 42 in one end of a link 43 which is preferably adjustable as to length. The lower end of the link 43 is pivotally connected at 44 to the lower end of one of the links 32 and to the adjacent end of one of the foot levers 30.

If the motor M is given a partial anti-clockwise rotation, the crank-pin 4| will move upward, causing corresponding upward movement of the links 32 and swinging the cutter I8 away from. the cloth support 25.

A seam-detecting device is provided for controlling the operation of the motor M, which device preferably comprises a detector bar or roll 50 (Fig. l) suspended by arms from fixed pivots 52 and normally positioned adjacent the lower guide-roll 2|. A projection 53 (Fig. 3) on one of the arms 5| engages a plunger 54 in a detector switch 55. A circuit-closing plate 56 is pressed yieldingly to the left in Fig. 3 by a spring 5'! and when in left-hand position closes a circuit through the wires 58 and 59. When the circuit is thus closed through the detector switch 55, a solenoid 60 (Fig. 4) is energized, which in turn operates through a time delay switch mechanism 60 to close a motor-control switch BI and start the motor M. The time delay mechanism forms no part of the present invention and is shown in my prior Patent No. 2,020,877.

The motor M is of the type which has a brake mechanism incorporated therein which acts directly on the armature shaft, preferably through a brake drum secured thereto. An electro-magnetic break release coil 62 is provided in parallel with the motor M, so that when the motor is put in operation, the brake will be released, but as soon as the motor circuit is broken, the brake will be applied.

Having described the details of construction of my improved seam-protecting mechanism, the operation and advantages thereof will be readily apparent. The cutter l8 and cloth support 25 remain in their normally adjusted relation until a seam S (Fig. 3) swings the detector bar 5|) and arms 5| to the left, thus permitting the spring 5'! to close the detector switch 55, which causes the coil 60 to be energized and to effect through the time delay mechanism (ill the closing of the motor control switch 6|.

The motor M then makes a partial anti-clockwise rotation as indicated by the arrow a in Fig. 2, moving the crank arm 40 toward the full line position shown in Fig. 2 and simultaneously swinging the cutter or revolver 18 away from the fixed cloth support 25.

During this movement the coil 62 releases the brake from the brake drum on the motor shaft, so that the full power of the motor is available to lift the cutter IS. The detector bar immediately returns to its normal position after the passage of the seam and again opens the detector switch 55 but the time delay switch mechanism 60 continues its control of the switch 5|. When the seam is clear, the motor circuit will be broken and the brake release coil 62 will be rendered inoperative, thus permitting application of the brakes to resist the backward rotation of the motor shaft which will be caused by the unbalanced weight of the cutter I8 and parts associated therewith. The brake will be adjusted so that it will resist but not prevent such backward return movement of the motor shaft and connected parts.

It should be noted that while the braking action is substantially constant, the weight of the cutter I 8 and associated parts is less effectively exerted against the braking force as the arm 40 approaches the dotted position in Fig. 2 and as the cutter approaches normal position. 'Consequently the braking effect is relatively and progressively increased as the return movement of the cutter to normal position approaches completion.

My improved seam-protecting mechanism will accordingly operate to remove the cutter quickly from cutting position, but will retard the return movement thereof sufficiently to prevent jar or shock. In actual operation, my improved mechanism operates very smoothly and the long and heavy cutter or revolver is displaced and returned without occasioning any objectionable jar or vibration in other parts of the machine. The period during which the cutter is out of operative position may be varied by various adjustments in the time delay switch mechanism 60.

The slot 42 in the link 43 provides a lost-motion connection which permits the cutter to be moved manually at any time.

Having thus described my invention and the advantages thereof, I do not Wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what I claim is:-

1. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said parts, and means to apply frictional resistance to retard the restoration of said parts to initial relation under gravity, said retarding means including connections through which the force of gravity acts less effectively to overcome said retarding means as the separated parts approach normal relation.

2. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said parts, and means to apply frictional resistance to retard the restoration of said parts means applying substantially constant frictional force and the force of gravity acting less effectively to overcome said retarding means as the separated parts approach normal relation.

3. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said cutter and support, said parts being thereafter restored by gravity to their initial relation, a seam-detecting device controlling said poweractuated means, and means additional to said power-actuated means operative to apply frictional resistance to retard the restoration of said parts under gravity to initial relation, said retarding means including connections through which the force of gravity acts less effectively to overcome said retarding means as the separated parts approach normal relation.

' 4. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said cutter and support, said parts being thereafter restored by gravity to their initial relation, a seam-detecting device controlling said power-actuated means, and means to apply frictional resistance to retard the restoration of said parts under gravity to initial relation, said friction-applying means being inoperative during the separation of said parts'by said power-actuated means, and the force of gravity acting less effectively to overcome said retarding means as the separated parts approach normal relation.

5. In a cloth shearing machine having a revolving cutter and an associated cloth support,

in combination, power-actuated means to separate said cutter and support, said parts being thereafter restored by gravity to their initial relation, a seam-detecting device controlling said power-actuated means, a brake device, and means to apply said brake device to retard such movement of restoration under gravity and the force of gravity acting less effectively to overcome said retarding means as the separated parts approach normal relation.

to initial relation under gravity, said retarding 6. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said cutter and support, said parts being thereafter restored by gravity to their initial relation, a seam-detecting device controlling said power-actuated means, a brake device, and means to apply said brake device to retard such movement of restoration under gravity, the brake-applying force being substantially constant but the effectiveness of application of gravity to overcome said retarding means progressively decreasing as the separated parts approach normal position.

7. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, revolvable means to separate said cutter and support, power means to give said revolvable means a partial revolution in one direction only to separate said cutter and support, said power means being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation by gravity, and means to yieldingly resist such backward return movement of said power means.

8. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, means to separate said cutter and support comprising an actuating link, a revolvable crank arm, a crank-pin thereon and an operating connection between said crank-pin and link, power means to give said arm a partial revolution in one direction only to separate said cutter and support, said power means being thereafter turned backward to initial position by the weight' of the connected parts as said cutter and support are restored to initial relation by gravity, and means to yieldingly resist such backward return movement of said power means.

9. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, revolvable means to separate said cutter and support, power means to give said revolvable means a partial revolution in one direction only to separate said cutter and support, said power means being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation by gravity, a brake, and means to apply said brake to said power means during its backward return movement only.

10. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, power-actuated means to separate said cutter and support, said means comprising an actuating link, a revolvable crank arm, a crank-pin thereon and an operating connection between said crank-pin and link, power means to give said arm a partial revolution in one direction only to separate said cutter and support, said power means being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation by gravity, a brake, and means to apply said brake to said power means during its backward return movement only.

11. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, a revolvable motor effective to separate said cutter and support by a partial revolution only of said motor, a seam-detecting device controlling the operation of said motor, said motor being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation, a brake, and means to apply said brake to said motor during its backward movement only.

12. In a cloth. shearing machine having a. revolving cutter and an associated cloth support, in combination, a revolvable motor effective to separate said cutter and support by a partial revolution only of said motor, a seam-detecting device controlling the operation of said motor, said motor being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation, a brake for said motor, and a magnetic release for said brake, said magnetic release being operative only when said motor is energized.

3. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, an electric motor connected and efiective to separate said cutter and support, a brake for said motor, a magnetic release for said brake, a main electric circuit having parallel branch circuits for said motor and said magnetic release, and a seam-detecting device effective to control said main circuit, whereby said brake is rendered inoperative when said motor is rendered operative and whereby said brake is operative only when said motor is inoperative.

14. In a cloth shearing machine having a revolving cutter and an associated cloth support, in combination, a motor effective to separate said cutter and support by a partial revolution only of said motor, a seam-detecting device controlling the operation of said motor, said motor being thereafter turned backward to initial position by the weight of the connected parts as said cutter and support are restored to initial relation, a brake for said motor, and. a magnetic release for said brake connected in parallel with said motor, whereby said motor and brake are rendered alternatively operative.

15. In a cloth shearing machine having a frame carrying a shearing unit, the combination of means to move said frame from normal operative position, and means additional to said moving means and operative to apply frictional resistance to control and retard the return movement of said frame under gravity to normal position, said retarding means including connections through which the force of gravity acts less effectively to overcome said retarding means as the separated parts approach normal relation.

CHARLES H. COOLIDGE. 

